Motion Blur on Armature Character really slow

Hi guys,

I have a heavy scene that takes 10 Gigs to render and about 10 hours per frame. When I turn on Motion blur and depth of field, my render time shoots up to 100 hours. I don’t think this is normal, or is this normal? Just seems like motion blur and depth of field shouldn’t slow it down so dramatically. This is with Blender 2.79.

***I repost this in Lighting and Rendering. Mod please delete.